Lysimachia nanshanensis (Primulaceae), a new species from southwest Hunan, China

<i>Lysimachia nanshanensis</i>, a new species of Lysimachia ser. Paridiformes discovered in Nanshan National Park of southwest Hunan, China, is described and illustrated. Morphologically, this new species most closely resembles <i>L. sciadantha</i> in having whorled leaves and terminal umbels but differs from <i>L. sciadantha</i> by having terminal umbels without a peduncle, subpapery leaves with obvious black glandular punctation and striation, longer pedicels, and filaments that are nearly free. Results of molecular phylogenetic analysis, based on nuclear ribosomal internal transcribed spacer (nrITS) and two chloroplast DNA fragments (<i>matK</i> and <i>rbcL</i>) of 34 <i>Lysimachia</i> species, showed that <i>L. nanshanensis</i> is closely related to <i>L. sciadantha</i>. According to the IUCN Red List Categories and Criteria, the new species is assigned to the Vulnerable (VU D1) category.